1. Field of the Invention
The invention relates to machine learning, especially in the context of generating motion recognizers from example motions; in some embodiments, a set of generated motion recognizers can be incorporated into end-user applications, with the effect that those applications are capable of recognizing motions.
2. Related Art
Writing program code to recognize whether a supplied motion is an example of one of an existing set of known motion classes, or motion types, can be difficult. This is because the representation of a motion can often be counterintuitive. For example, if a motion is created with a device containing at least one accelerometer, relating the resulting data to an intuitive notion of the motion performed can be extremely difficult with known techniques. The problem is difficult because the same motion can be quite different when performed by different people, or even by the same person at different times. In addition the motion recording device might introduce measurement errors, or noise, that can make it harder to recognize a motion.
Handwriting recognition (HWR) is a special case of recognizing motions. What makes it a special case is that the set of motion classes is known in advance and all the motions are known ahead of time to be performed in a two-dimensional plane. For example, in English there are 26 lowercase letters of the alphabet that are written on a flat writing surface. Real world HWR recognition systems may include support for uppercase letters, punctuation, numerals and other gestures such as cut and paste. At least some machine learning approaches to HWR are known and widely used, but they do not solve the more general problem of generating motion recognizers in response to example motions.
At least some techniques for gesture recognition of limited symbols in computer games are also known. For example, various spell-casting games allow players to perform gestures that are recognized as invocations for particular spells. However, the set of gestures is fixed in advance by using a pre-programmed recognizer. Moreover, a movement is usually restricted to movement in a plane.